diff options
| author | Daniel Thompson <daniel.thompson@linaro.org> | 2015-01-12 15:42:24 +0000 |
|---|---|---|
| committer | Daniel Thompson <daniel.thompson@linaro.org> | 2015-07-03 15:54:12 +0100 |
| commit | 887ac63d67bf319e5dc54e491fbc518bee73712b (patch) | |
| tree | ff48aa4886720d783faec52b116026d866664214 /include | |
| parent | a9021c82a05d96b019a52d53ade4d6584abdfb0d (diff) | |
printk: Simple implementation for NMI backtracing
Currently there is a quite a pile of code sitting in
arch/x86/kernel/apic/hw_nmi.c to support safe all-cpu backtracing from NMI.
The code is inaccessible to backtrace implementations for other
architectures, which is a shame because they would probably like to be
safe too.
Copy this code into printk, reworking it a little as we do so to make
it easier to exploit as library code.
We'll port the x86 NMI backtrace logic to it in a later patch.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/printk.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/printk.h b/include/linux/printk.h index 9b30871c9149..265a1399a731 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -228,6 +228,26 @@ static inline void show_regs_print_info(const char *log_lvl) } #endif +#ifdef CONFIG_PRINTK_NMI_BACKTRACE +/* + * printk_nmi_backtrace_prepare/complete are called to prepare the + * system for some or all cores to issue trace from NMI. + * printk_nmi_backtrace_complete will print buffered output and cannot + * (safely) be called from NMI. + */ +extern int printk_nmi_backtrace_prepare(void); +extern void printk_nmi_backtrace_complete(void); + +/* + * printk_nmi_backtrace_this_cpu_begin/end are used divert/restore printk + * on this cpu. The result is the output of printk() (by this CPU) will be + * stored in temporary buffers for later printing by + * printk_nmi_backtrace_complete. + */ +extern void printk_nmi_backtrace_this_cpu_begin(void); +extern void printk_nmi_backtrace_this_cpu_end(void); +#endif + extern asmlinkage void dump_stack(void) __cold; #ifndef pr_fmt |